In the brick room following the first door, there is a misaligned section of wall to the east. Open it to find security armor and a box of shells. (sector 266)

At the northern outdoors section, the western building has a switch in the southeast corner. Flip it, and then enter the central building. Climb the water-covered steps in the center, and then attempt to head back down. You will be warped to five armor bonuses and two cells. (sector 254)

In secret #2, follow the trail of items, and you will be teleported to a platform with a rocket and a cell. (sector 268)